<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		
		<style>
			
			*{
				box-sizing: border-box;
				
				position: relative;
			}
			
			div.box	{
	
				width: 500px;
				height: 600px;
				border: 1px solid black;
				
				/* position: relative; */
				
			}
			
			
			
			/* 根据父元素高度进行计算   设置margin-top
			 
			 600 -30  = 570
			 
			 570 /2 =  285
			 
			 */
			.box button {
				/* height: 100%; */
				padding: 5px;
				float: right;
				
			/* 	margin-left: 5px;
				margin-right: 5px; */
				/* vertical-align: middle; */
				
				/* margin: auto  0 ; */
				display: inline-block;
				margin-top: 285px;
				
				/* margin-top: 50%; */
				
			
			}
			
			
		</style>
	</head>
	<body>
		
		
		
		<div class="box">
			
			
			<span>this is pan.</span>
			
			<button>hello</button>
			<button>hello2</button>
			<button>hello3</button>
		</div>
		
	</body>
</html>